Structural unit



June 17, 1941. H. s. NAGIN ET AL STRUCTURAL UN I T Filed July 1, 1958 INVENTOR5 Lm MMPN k n am 0 N W 5 5 n a 2 HL Patented June 17, 1941 STRUCTURAL UNIT Harry S. Nagin and Leslie Strickland, Pittsburgh,

Pa., assignors to Reliance Steel Products Company, Rankin, Pa., a corporation of Pennsyl- Vania Application July -1, 1938, Serial No. 216,999

1 Claim.

The present invention relates in general to structural units and is particularly applicable to open or skeleton metal structural units such as beams, joists, girders and columns. Such truss-like structures, while light of weight, are strong, rigid and economical to fabricate and are well adapted for use instead of beams in carrying light loads such as in the case of joists in floors and the like; and may also be employed to advantage as a column, as a roof purlin, and as a reinforcement for concrete floors.

One of the objects of the invention is to provide a structural unit preferably of the trusslike type with a novel and simple connection between the upper and lower chords, whereby great strength and rigidity are obtained, together with high resistance to stresses.

By means of our invention, we provide a composite structure which can be readily fabricated from standard shapes by electric welding. Such a structure is of maximum strength and minimum weight and is rigid.

In the accompanying drawing, there is shown for purposes of illustration only a preferred embodiment of our invention.

In the drawing:

Figure 1 is a side elevation of a portion of a joist constructed in accordance with our inventicn, and

Figure 2 is a View along the line IIII of Figure 1.

In Figures 1 and 2 there is shown a section of a metal joist which consists of a topchord 5t and a bottom chord II and a zigzag web rod or strut I2 connected at alternate bends to the spaced apart upper and lower chords. The top chord I0 is formed from two angles placed back to back in spaced apart relation with the web rod l2 interposed between them. The legs of each of the angles project outwardly and downwardly as shown in Figure 2. The web rod or brace I2 is formed from a square bar set on edge and is secured tothe angles by electric resistance welding or by spot welding. The bottom chord H is likewise formed from angles, the legs of each of which face upwards and outwards and are spaced apart so as to accommodate the web rod I2.

While we have illustrated and described a certain preferred embodiment of our invention, it will be understood that the invention is not limited thereto but that various changes in the shape, size, number, and arrangement of parts may be resorted towithout departing from the spirit of our invention or the scope of the following claim.

We claim:

In a structural unit, an upper chord.comprising a pair of laterally spaced apart angle members having one leg extending vertically down wardly, the other leg extending outwardly, a lower chord spaced'from the upper chord, said lower chord comprising a pair of laterally spaced apart angle members having one leg extending vertically upwardly, the other leg extending outwardly, and a zigzag web member interposed between the chords and having portions thereof entered between each pair of the angle members forming each chord and electric resistance welded to the vertical legs, the zigzag member being formed from a square bar so that one diagonal of the cross-section of the bar is substantially constantly in the vertical plane passing through the longitudinal axis of the unit.

HARRY S. NAGIN. LESLIE STRICKLAND. 

